Terrazzo grinding apparatus



NOV. 13, A w

TERRAZZO GRINDING APPARATUS Filed June 10, 1933 7 Sheets-Sheet Nov. 13, 1934. w MALL 1,980,491

TERRAZZO GRINDING APPARATUS Filed June 10, 1955 7 Sheets-Sheet 2 INVENTOR.

Q-flur M 4 ,14 6a.. ATTORNEY.

A. W, MALL TERRAZZO GRINDING APPARATUS Nov. 13, 1934.

T Sheets-Sheet 4 Filed June 10, 1933 1 I 11 INVENTOR.

g ATTORNEY.

Nov. 13, 1934. A. w. MALL TERRAZZO GRINDING APPARATUS Filed June 10, 1933 '7 Sheets-Sheet 5 Nov. 13, 1934. A, w MALL 1,980,491

TERRAZZO GRINDING APPARATUS Filed June 10, 1933 4 7 Sheets-Sheet 6 Nov. 13, 1934. A. w. MALL TERRAZZO GRINDING APPARATUS Filed June 10, 1935 7 Sheets-Sheet I INVENTOR. @fir MZZ BY I WWW

ATTORNEY.

Patented Nov. 13, 1934 STATES PATENT OFFICE 14 Claims.

My invention relates to a new and useful improvement in apparatus for grinding terrazzo floors and like devices.

My invention relates more particularly to jfundamental improvements in machines of this type whereby the head which supports the grinding wheel rests of its own weight upon the floor to be ground.

An object of the present invention is to provide an improved grinding, scrubbing or polishing machine or like device.

A further object is to provide an improved grinding, scrubbing or polishing machine of the class described capable of operating at a greatly increased rate of speed.

A further object is to provide an improved machine of the class described which has means for changing the position of the motor with respect to the grinding Wheel so that more or less of the weight of the frame and motor may be applied to compensate for the wear on the grinding wheel or for any other purpose.

A further object is to provide an improved machine of the type having a horizontal motor in which the frame for supporting the same is greatly simplified and lightened, thus making a substantial saving in the initial cost of a machine of this type.

A further object is to provide an improved means for guiding or protecting the walls of buildings when terrazzo floors are being ground.

A further object is to provide an improved splash and safety guard that adjusts itself automatically to the height of the grinding wheel.

A further object is to provide a machine of the type described that is extremely simple in construction, yet rugged and capable of long wear and usage without being damaged or worn out.

Other objects and advantages will be more apparent from the following description wherein reference is had to the accompanying seven sheets of drawings upon which- Fig. 1 is a side elevational view of my improved apparatus shown in connection with a grinding wheel. The view has parts broken away in section to more clearly show other parts.

Fig. 2 is a rear elevational view of the machine;

Fig. 8 is a vertical sectional view of the grinding wheel carrier and driving head;

Fig. 4 is a plan sectional View taken on the line 4-4 of Fig. 3;

Fig. 5 is a vertical fragmentary section showing the manner in which the grinding head is flexibly supported;

Fig. 6 is a sectional view illustrating the flexible drive from the motor to the driving head;

Fig. 7 is a plan view of a modified form of guard and splash device;

Fig. 8 is a vertical sectional view taken on the line 8-8 of Fig. 7;

Fig. 9 is a side elevational view of a modified form of the apparatus showing an auxiliary carriage which may be employed;

Fig. 10 is a vertical sectional view taken generally on the line 10--10 of Fig. 9; and

Fig. 11 is a modified view of the flexible connection shown in the form of the invention of Figs. 9 and 10.

Referring particularly to Fig. 1, the apparatus comprises generally a motor 10, a flexible shaft 12, a grinding head 14 to which a grinding wheel 16 is attached, and a carriage or support 18.

The motor 10 may be of the special type of heavy-duty motor that is vapor and dust-proof, and which is capable of approximately double momentary overload so that by furnishing a 7 H. P. motor for a specific duty, a double momentary overload may be obtained without injuring the same.

The motor 10 carries at its forward end a bracket 20 which is securely bolted thereto and in which a cross-shaft 22 may be supported adjacent the lower end of the motor. A pair of arms 24 may extend rearwardly from the bracket 20and carry at their rearward end stub shafts 26 upon which support wheels 28 are adapted to be mounted. The wheels 28 may be provided with the rubber tire portions 30 which provide a better and firmer grip upon the floor during the operation of the machine, and for the further purpose of eliminating any possibility of marring or scratching the floor surface.

The motor 10 may carry directly thereabove a tank or water reservoir 32 and may support the same by a plurality of strap members 34 which extend upwardly from suitable positions upon the casing of the motor 10. The cover for the reservoir 32 may have a built-in funnel 36 and screen, (not shown) and have an'outlet adjacentits lower edge controlled by a valve member 38. A flexible hose 40 may extend forward from the valve 38 to the driving head 14 and be connected thereto by a suitable elbow member 42.

A means for drawing the apparatus from place to place may comprise the U-shaped handle member 44 that is pivotally secured to the motor at the points 46. A switch box 48 may be conveniently secured to the handle 44 from which a flexible cord 50 may extend to any available wall socket and from which a conduit 52 may extend to the motor 10.

Means for raising or lowering the motor 10 upon the wheels 28 include a handwheel 54 provided with a screw member 56 that is attached to a link 58 pivotally connected at 60 to an arm 62. The arm 62 may be keyed to the shaft 22 and thus it can be seen that as the outer end through which the pivot 60 passes is raised, the rearward end of arm 24 to which the wheels 28 are attached will be lowered, thus raising or lowering the motor and the flexible shaft 1.2.

The link 58 may be slidably mounted in a suitable housing 64 that is pivotally secured at 65 to the bracket 20.

The flexible shaft 12 may be of any desired type and in the embodiment shown in the drawings I provide a shaft having a coiled spring member secured at one end to a core tip 71 that screwthreadedly engages the shaft 72 of the motor and at its opposite end engages a core tip 73 which frictionally engages in a hollow shaft member 74 to continue the drive therefrom.

The spring member 70 may be axially positioned in a flexible hose member '75 provided with the casing ferrules 76 and 77 which screw-threadedly engage at their opposite ends with the stationary portions 78 of the motor and 14 of the spindle housing respectively.

The spindle housing 14, as best shown in Fig. 3, may contain the hollow shaft members 74 and provide a suitable bearing in the form .of roller bearing members 79 and 80 to support the same therein.

The hollowshaft 74 may carry at its forward end a bevel gear 81 which in turn meshes with a vertically disposed bevel gear 82 that is keyed to a spindle 83.

The spindle 83 may have an upper bearing 84 adjacent its upper end in the housing 14 and may have a pair of ball bearing races 85 and 86 adjacent its lower end for supporting the same. The spindle 83 is formed at its upper end with a reduced passageway 88 through which a tubular member 89 is adapted to pass. The tubular member 89 may be fixedly mounted in a cap 90 mounted on the spindle housing adjacent the elbow member 42 which communicates with the water reservoir 32 through the flexible hose 4D. In this way water may be directed into the hollow spindle 83 and out through the bottomtherecf.

The spindle 83 may be screw-threaded at its lower end and engage in backing plate 92 of the grinding wheel 16. The grinding wheel 16, which may be of any suitable hard material such as carborundum or other grinding substances, may be formed with an inner bore 94 having a tapered wall 95 so that the same may be engaged by a retainer ring 96. The retainer ring may be fastened securely in place by means of the cap screws 97 and nuts 98 so that the grinding wheel will be effectively secured at the lower end of the vertical spindle 83. In this way an effective drive will have been provided from the motor 10 to the grinding wheel 16.

:wheel, andin this manner a guard is provided so I end of the spring member 105.

blear.

that the grinding wheel will not touch any side walls when in use in grinding a floor.

The frame 101 may preferably be formed of a heavy material such as lead, so that in addition to acting as a frame for the bumper or guard, a considerable weight is also provided directly over the grinding wheel and so that the grinding wheel itself has a tendency to ride the surface of the floor and thus eliminate chatter and vibration, due to the low center of gravity of the weight.

Means for supporting the spindle housing 14 are provided in the form of a resilient construction which may include the leaf-spring members 195 that extend forward from the frame member lar 109 and a ring-shaped nut member 114 which is screw-threadedly mounted on the collar and;

securely fastens the flexible member as shown.

From the above description it can be seen that the housing 14 is flexibly carried at the outer In effect a floating or universally flexible support for the housing, spindle and grinding wheel has been provided. The importance of this is believed tobe Whenever an irregularity in the floor is encountered, the grinding wheel 16 can conform to any desired surface contour and in view of the flexible drive and the flexible support for the housing of the spindle, there is no undue strain or wear upon any of the movable parts. The elimination of this unequal strain and torque has resulted in the making of a device which can be run at very high speeds as compared to those of the prior art. For example, the ordinary machine of the prior arthas a grinding wheel which rotates at a speed of about 350 to 400 R. P. M., whereas with applicants construction such as herein described, the grinding wheel 16 may be safely driven at a speed of 3500 R. P. M., which at once assures speedier and better work. Fura ther with the floating spindle housing or head construction devised, it is possible to feather and blend in uneven surfaces practically automatically, as the grinding wheel will assume the angle or slope of the surface and automatically grind off the uneven or unfinished edges in the floor.

In the event it is desired to manipulate the grinding wheel for certain angular cutting; an auxiliary handle 120 is provided, fastened to the housing 14 by suitable bolts 121 in such a'manner that the grinding wheel and housing can be tilted as desired by manipulation of the auxiliary handle 120. This may be done to concentrate on a small grinding surface when desired.

A further handle for lifting or moving the grinder may be provided adjacent the head or grinding wheel and maycomprise a. U-shaped rod member 122 which is slidably mounted in a pair of bracket members 123 that are fastened upon the spring members 105. A sliding fit is provided in the bore 124 of the bearings 123 so that the handle may be drawn out to provide a greater or lesser leverage.

The inner end of the handle 122 contains pin members 125 which limit the distance that the handle may be withdrawn. 7

In Figs. 7 and 8 of the drawings I have shown The flexible ring.

a modified construction of a guard which is in the nature of a safety or splash guard. The same may comprise a strap member 130 which may be fastened upon a collar 131 secured to the housing 14. The strap member may be provided with a plurality of outwardly extending bracket members 132 which carry at their outer end a ringshaped shield member 133. The shield member 133 may carry upon its outer surface a flexible rubberized or leather ring member 134 for a purpose which will be presently described.

With the guard shown in Figs. '7 and 8 positioned about the grinding wheel 16, it is thus apparent that the water which is fed through the hollow spindle 83 will not be thrown a great distance beyond the edge of the grinding wheel and thus water and sand which is thrown beneath the grinding wheel will not be disseminated or spread out as quickly with the result that more work will be done upon any given spot because of the fact that the water and sand have not all been thrown away from below the grinding wheel. Suitable adjusting features may be provided upon the guard so that the same may be moved as the grinding wheel wears down, and the guard will thus always bear against the floor and effectively prevent the spread of water and sand.

The metallic ring 133 may be in the nature of a spring ring so that the same will have some flexibility and allow a certain amount of give when working up against side walls. It is also preferable to provide an opening 136 at one spot on the periphery of the ring so that the grinding wheel 16 may be moved to within approximately of a side wall when it is desired to grind this close to the wall. When it is desired to close this opening, an additional member 137 in the form of an arcuately shaped strap is provided. This strap is adapted to be placed over the bolts 132 and loosely hang in position, thus effectively closing the opening to form a complete enclosure for the grinding wheel and confine the water and sand in this manner. By confining the sand and water within the enclosure provided, the grinding device may be employed for the purpose of power grouting in the surfacing of highways, and for the removal of bumps on concrete pavements the apparatus is used to grind down the pavement to a level.

After the surface has been cut down to the level desired, all that is necessary to obtain a finished surface is to provide a mixture of fine sand and cement on the highway and then rub in or power grout this material to fill up the air holes and make the surface smooth and level.

The physical effort necessary to rub in the particles of cement and sand to seal the surface is considerable and while this operation has heretofore been done by hand power only, it is believed to be obvious that by the use of the power device shown a much better and more efiicient job of rubbing in can be accomplished. With the method described, the pores of the pavement are closed much more satisfactorily than by any hand method, and therefore this particular surface One of the important things to remember when starting the high speed apparatus which I have described, is to keep the grinding wheell6, or

other rotary element, removed from the surface for a sufficient length of time to allow the motor to come to its proper speed. If this is not done, very serious damage may be done to the motor as well as the grinding wheel and the connected parts. To overcome the possibility of starting the device with the grinding wheel resting on the floor, I provide an auxiliary carriage means which may be secured to the shaft 22 and which may be manipulated by the handle member 44. This means may include a pair of arm members 140 which extend forward from the shaft 22 and carry at their forward ends support casters 141. The casters may be of the usual type mounted upon a revolvable spindle so that the same may be moved about in any direction.

The forward end of the arm 140 is pivotally connected to a socket member 142 within which the handle member 44 is positioned. The pivot 143 may be mounted in the member 142 and ride in the elongated slot 144 in arm 140. This slot may be covered by suitable shield members 145 to prevent the dust or dirt from accumulating therein.

The members 142 are pivotally attached to the bracket 20 that is connected to the forward end of the motor 10. A pair of segments 146 may be fastened upon opposite sides of the bracket 20 for a purpose which will be presently apparent. These segments may be provided with the slots 147 and l48 located at approximately 45 separations.

The upper slots 148 are normally engaged by bolt members 149 located at the lower end of a pair of operating rods 150 which extend upward through the hollow handle member 44, and are fastened at their upper ends to a pair of cylindrical guide members 151 which are likewise mounted in the hollow handle members 44. The members 151 may be connected by a suitable strap rrli ember 152 to effect the uniform operation there- 0.. member for this purpose.

The movement of the handle 44' from the position shown to engagement with the slot 147 of the sector 146 moves the casters 141 downwardly to engage the floor and tilt the motor 10, the spindle housing 14, the grinding wheel 16 and all associated parts upward as shown in the dotted lines to an angle of approximately 22. In this position the handle 44 is extended outwardly so that the device may be drawn about as desired by this handle.

A suitable slot 153 is provided in the handle When it has been drawn to a place where it is desired to operate the machine, the motor may be started and the grinding wheel be driven to its desired speed before the same is lowered to engage the working surface. In this way wear and tear upon the motor is prevented to a high degree, thus ensuring a longer life and better operation of the motor and associated parts.

A slightly modified form of raising and lowering device with the hand wheel 54 is provided. This may include a screw member 56 which extends into a socket 57 in the housing 20 and serves to move a bolt member 59 upwardly and downwardly between the cover member 20a and the lower wall 23?) of the housing.

The nut member 59 may carry the link members 58' which are in turn attached at their lower end to the stub shaft 60. The stub shaft 60 is connected in the manner previously described by raised or lowered upon its supporting carriage.

A modified form of guard member 160 is shownv in Fig. 9. This guard member may comprise a shell portion 161 having the inwardly turned flange portion 162 which rests upon an outwardly turned flange 163 of, a. weight member 164 secured to the spindle housing 14.

The shell member is adapted to carry around its outer periphery a rubberized fabric guard member 165 which will bear against the floor and as the grinding wheel is worn'oif the guard will rise due to the fact that his loosely supported upon the flange 163; Thus an effective guard member has been provided which will automatically retain its position on the floor regardless of the size of the grinding wheel or the amount which the same has been worn.

In Fig. 11, I illustrate a modified form of flexible connection wherein I employ the flexible disk collar member 166 securely fastened between shoulder 167 of the housing and a nut member 168. The outer end of this flexible disk may be fas- ..tened between a pair of ring members 169 and 170 by the bolt and nut connection 171. The metallic rings 169 and 170 may be fastened in any suitable manner to the spring member 105 so that by the above construction an extremely flexible f1 arrangement is provided.

While I have illustrated and described a specific embodiment of the invention and some modifications thereof, it will be understood that numerous modifications and changes may be made in the "jdetails shown and I do not wish to be limited in any particular. Rather, what I desire to secure and protect by Letters Patent of the United States 1. The combination of a horizontally disposed motor, a flexible shaft extending therefrom, a

wheeled support secured to said motor at one end thereof, a vertically disposed face grinding wheel supported at the end of said flexible shaft and cantilever spring means for supporting the same,

"said spring means extended from said wheel support.

2. A grinding, scrubbing or polishing machine comprising a horizontally positioned motor, a bracket secured to the forward end of said motor, a plurality of support wheels secured to said bracket, means comprising a handwheel and screw associated therewith for raising or lowering said motor, a flexible shaft extending forward from said motor, a vertical spindle driven thereby, a housing for said spindle, a vertically disposed face grinding wheel secured to the lower end of said spindle and a cantilever spring member extended from said bracket for supporting said housing.

3. A scrubbing, grinding or polishing machine comprising a horizontally positioned motor, a bracket secured to the forward end of said motor, a plurality. of support wheels secured to said bracket, means associated therewith for raising or lowering said motor, a flexible shaft extend ing forward from said motor, a vertical spindle driven thereby, a housing for said spindle, a vertically disposed face grinding wheel secured to the lower end of said spindle, and a cantilever spring member extended from said bracket for supporting said housing.

4. A scrubbing, grinding or polishing machine comprising a horizontally positioned motor, a bracket secured to the forward end of said motor, a plurality of support wheels secured to said bracket, means comprising a handwheel and screw associated therewith for raising or lowering saidt motor, a flexible shaft extending forward from; said motor, a vertical spindle driven thereby, a housing for said spindle, a pair of cantilever spring members extendedfrom said bracket for supporting said housing, avertically disposed face grinding wheel, secured to the lower. end, of said spindle, and a water supply extending to 'ie axis of said working member.

5. A terrazzo grinding machine comprisingv a horizontally positioned. motor, a water reservoir mounted thereon, a bracket secured to the forward end of said motor, a plurality of support, wheels secured to said bracket, means comprising a handwheel and screw associated therewith for raising or. lowering said motor, a continuous. flexible shaft extending forward from said motor,- a vertical spindle driven thereby, a housing for said spindle, spring means extended from said bracket to support said housing, a flexible collar on said housing, said spring means secured thereto, a horizontally disposed grinding wheel se-' sitioned motor mounted thereon, a: flexible drive shaft extending therefrom, a vertical spindle driven thereby, a housing for said spindle, cantilever springs for resiliently supporting said housing for universal tilting movement, a vertically disposed grinding wheel secured to the lower end of said spindle and a handle attached to said housing to allow manual tilting of said grinding wheel.

7. The combination in a terrazzo grinding machine of a wheeled supporting frame, a hori+ zontally positioned motor mounted thereon, a water reservoir positioned on said motor, a flexible drive shaft extending therefrom, a hollow vertical spindle driven thereby, a housing for supporting said spindle, cantilever springs for resilientlysupporting said housing for universal tilting movement, a vertically disposed grinding wheel secured to the lower end of said spindle and a water conduit extending from said reservoir through said spindle to the interior of said grinding wheel.

8. A grinding machine comprising a horizontally positioned motor, a bracket secured to the forward end of said motor, a plurality of support wheels secured to said bracket, means comprising a handwheel and screw associated therewith for raising or lowering said motor, a flexible shaft extending forward from said motor, a vertical spindle driven thereby, a housing for said spindle, a pair of spring members extended from said motor bracket for yieldingly supporting said housing, a horizontally disposed grinding wheel secured to the lower end of said spindle, and means for automatically supporting said grinding-wheel spaced from the grinding surface.

9. A grinding machine comprising a horizontally positioned motor, a bracket secured to the forward end of said motor, a plurality of support wh els secured to said bracket, means associated, therewith for raising or lowering said motor, a flexible shaft extending forward from said motor, a vertical spindle driven thereby,a housing for said spindle, a pair of spring members extended from said motor bracket for yieldingly supportsaid housing, a horizontally disposed grinding wheel secured to the lower end'of said spindle, and means including an auxiliary carriage for normally supporting said grinding wheel spaced from the grinding surface.

10. A terrazzo floor grinding machine comprising a carriage, a horizontal motor mounted thereon, a grinding head, a flexible shaft between said motor and said head, a grinding wheel in said head, a universally flexible support for said grinding head, and manually operable means for tilting said grinding wheel, said flexible support means adapted to instantly return said grinding wheel to normal position upon releasing said manually operable means.

11. The combination of a horizontally disposed motor, a flexible shaft extending therefrom, a wheeled support secured to said motor at one end thereof, a universally tiltable grinding wheel supported at the end of said flexible shaft, spring means for supporting the same, said spring means extended from said Wheeled support and a flexible collar at said grinding wheel, said spring means adapted to be secured thereto.

12. The combination in a terrazzo grinding machine of a horizontally disposed motor, a fluid supply associated therewith, a wheeled support secured to said motor, a flexible shaft extending from said motor, a universally tiltable face grinding wheel at the end of said shaft, a pair of cantilever spring members for supporting same, and a conduit from said fluid supply to the center of said grinding wheel.

13. The combination in a terrazzo grinding machine of a horizontally disposed motor, a fluid supply associated therewith, a Wheeled support secured to said motor, a flexible shaft extending from said motor, a hollow vertical spindle driven thereby, a universally tiltable face grinding wheel at the end of said spindle using a pair of cantilever spring members for supporting the same and a conduit from said fluid supply connecting with said spindle to feed water to the center of said grinding wheel.

14. The combination of a horizontally disposed motor, a flexible shaft extending therefrom, a wheeled support secured to said motor at one end thereof, a universally tiltable grinding wheel supported at the end of said flexible shaft, a pair of cantilever spring members extending from said motor for supporting the same, and a flexible collar at said grinding wheel, said spring means adapted to be connected thereto.

ARTHUR WILLIAM MALL. 

